Immunoactive two-dimensional self-assembly of monoclonal antibodies in aqueous solution revealed by atomic force microscopy

High-resolution atomic force microscopy coupled with a frequency modulation method is used to visualize flexible, monoclonal immunoglobulin G (IgG) antibodies and their interactions with antigens in aqueous solutions. IgG molecules, which individually have Y-shaped structures, self-assemble into hexamers that form crystalline two-dimensional arrangements on a mica substrate, and are observed to retain their immunoactivity within the crystal.